The Ligand Assay Core has been a component of the University of Chicago DRTC since it was first funded in 1977. At the last competitive renewal, the Core was judged to be of outstanding merit. The overall objective of this Core is to help independently funded investigators carrying out research in diabetes and other metabolic disorders by assaying insulin, C-peptide, proinsulin and other hormones. The specific objectives of this Core are: a. to advise and aid independently funded investigators in assaying insulin and other hormones relevant to the study of diabetes and related disorders; b. to develop and implement new assays that may be required by users of the Core Laboratory and modify existing assays to improve throughput and reduce cost; c. to train investigators, fellows, students and other laboratory personnel in the procedures of the Core. Specific services to be offered by this Core are: a. Assays of hormones involved in the control of carbohydrate metabolism including insulin (human and rodent), C-peptide, proinsulin, insulin antibodies, glucagon, pancreatic polypeptide, growth hormone, leptin, cortisol, and free fatty acids; b. Advice and aid to independently funded investigators in methods of assaying insulin and other hormones; c. Development and implementation of new assays that may be required by users of the Core Laboratory and modification of existing assays to improve throughput and reduce cost; d. Training of investigators, fellows, students and other laboratory personnel in the procedures of the Core Laboratory. Dr. Samuel Refetoff will serve as Director and Dr. David Ehrmann will serve as Co-Director.